Make sure to adapt "home/user" to your user. You can remove the backup folder database_backup after you start CUBRID and check if the databases are running correctly.

Important! Make sure that /var/opt/cubrid/databases/databases.txt file contains the right paths to the database folders.

If you want to perform a completely safe upgrade indepent of the CUBRID version, instead of copying the databases folder like in the above approach, you should use cubrid unloaddb to export all databases in a backup folder, then uninstall CUBRID, update repository and install the new CUBRID version. Finally, you must import the databases into the new CUBRID instance by running cubrid loaddb.